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The USRP™ Hardware Driver Repository
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USRP B210 change gain type to Normalized #694

Closed aldalahmeh closed 11 months ago

aldalahmeh commented 11 months ago

Issue Description

I am using a USRP B210 with srsRAN 5G Project and COTS UE (a rooted android phone) to setup a 5G network. Of course, the B210 uses the UHD. However, using the standard configuration the transmitted power is around -125dBm, which is sufficient for the UE to detect.

Just to make sure, I create a flowgraph in GNURadio for an AM transmitter with default USRP setting and got the same low power issue. The flowgrqaph pic is attached below. However, when I changed the RF options [Ch0 Fain Type: Normalized], I got up to -67dBm, see pic below.

am_gnuradio

fl_setting

I found how to do that in the python code by using self.uhd_usrp_sink_0.set_normalized_gain(1, 0)

What is the way to do it in C or the C API provided with the UHD?

Setup Details

Expected Behavior

Actual Behaviour

Steps to reproduce the problem

Additional Information

NI-LAm commented 11 months ago

@aldalahmeh There is no set_normalized_gain in the UHD API (neither in C/C++ nor Python). But there are functions for RX and TX. Given your example I assume you are looking for the TX version. Just have a look into the C API definition of UHD. We also have some examples for the C API that can be found here https://github.com/EttusResearch/uhd/tree/master/host/examples (everthing with .c extension). This could be a good starting point to adapt for your use case.

I will close this as complete. Feel free to reopen, if that doesn't answer your question.

Regards Lars

aldalahmeh commented 11 months ago

OK, found the C++ function "set_normalized_tx_gain" defined in the (uhd/host/lib/usrp/multi_usrp.cpp), as you have pointed. It seems that the default value is 0, which is the smallest gain. Thanks